【作者】 李金涛；

【导师】 王江涛； 赵卫红；

【作者基本信息】 中国海洋大学 ， 海洋化学， 2004， 硕士

【摘要】 近年来，由于受人类活动的影响，长江口邻近海域富营养化程度逐年加重，范围逐年扩大，从而导致了海水水质恶化、海洋生态环境失衡、发生大面积有害赤潮等一系列的海洋生态环境问题。本文总结了国内外学者对海洋浮游植物与营养盐之间的关系研究，重点研究了中国典型赤潮高发区——长江口邻近海域浮游植物的营养限制状况、重要营养物质对海洋浮游植物生长过程中生物量及浮游植物种类组成的影响、浮游植物生长过程中对营养盐的迁移转化过程等一系列的热点问题，为进一步了解该海域有害赤潮的发生机理、控制因素等的研究提供科学基础。主要有以下研究成果： 1．用现场调查及现场营养盐加富生物测定法对长江口邻近海域浮游植物夏季、冬季的营养盐限制状况进行了研究。研究结果表明： 1．1 通过现场培养实验，海水中存在浮游植物营养限制因子，浮游植物的生长将明显受到限制，消除这种限制因子以后浮游植物会快速增殖。 1．2 调查海域在近长江口透明度低于1m的海域，冬季和夏季浮游植物都是受光限制的低生产力海区。调查海域范围内夏季初级生产力高值区主要集中在舟山渔场和长江口以北两个区域，介于盐度范围28—31之间的海域。冬季的高初级生产力海区向东南方向移动，初级生产力总体水平远不及夏季。 1．3 调查海域夏季浮游植物生长的受限情况划分为4个区域：Ⅰ，近河口光潜在限制区。Ⅱ，磷酸盐潜在限制区。Ⅲ，N、P潜在限制过度区。Ⅳ，N潜在限制区。 1．4 调查海域冬季浮游植物的生长划分为3个区域：Ⅰ，近河口光潜在限制区。Ⅱ，P潜在限制区。Ⅴ，非营养潜在限制区。 1．5 盐度在31分界限的两侧是浮游植物N、P限制季节交替变化明显，夏季为N、P潜在限制区；冬季该海域不存在营养潜在限制。口门区和冲淡水区的潜在限制因子分别是光和P，且季节变化不大。 1．6 在调查海域范围内不存在浮游植物Si、Fe潜在限制。 2．通过现场加富培养实验的方法对长江口邻近海域海水营养盐对浮游植物生物量及浮游植物种类组成的影响，浮游植物对营养盐的迁移转化进行了研究。结果表明： 2．1 在现场培养实验中，在P限制的情况下，浮游植物的生物量随活性磷酸盐浓度长江口邻近海域营养盐对浮游植物生长的影响 的升高而升高，在N限制的环境中浮游植物生物量也随硝酸盐浓度的升高而 递增。2.2近河口海域，在营养盐浓度较高的情况下，营养盐的绝对浓度对浮游植物的影 响较比例的影响更明显。近河口赤潮高发区站位的培养实验中营养盐的加富对 浮游植物生长的促进作用没有其它远离河口的非赤潮高发区站位明显。2.3从三个航次对赤潮海水的现场培养实验可以看出，在发生赤潮的情况下，在培 养过程中赤潮浮游植物种类一般会保持优势，其它浮游植物种类很难快速生长 而形成优势。2.4没有发生赤潮海水的培养种群交替变化明显，缺乏营养盐的环境中东海原甲藻 始终具有较强的生命力，营养盐加富的情况下则很快被硅藻(中肋骨条藻)压 制。2.5在高于Redfield比值的环境中，浮游植物对硝酸盐的吸收依赖于培养介质中磷 酸盐的浓度。低于Redfield比值的环境中，浮游植物对硝酸盐的吸收依赖于培 养介质中硝酸盐的浓度;随硝酸盐浓度的变化，浮游植物对磷酸盐的平均吸收 速率相差不大。2.6在培养实验加富的阐值范围内，浮游植物会很快将大部分无机溶解态营养盐吸 收，逐渐转化为其它形式的营养盐(溶解有机态、颗粒态)，溶解有机态和颗 粒态营养盐的矿化过程也很快，在培养实验的后期浓度就开始下降。2，7在现场培养体系中浮游植物生长使水体中的生物碳、氮比例增加，使水体中的 颗粒C加比值降低，浮游植物死亡使水体中颗粒C肘比值升高。更多还原

【Abstract】 In recent years, influence by the activity of human beings, eutrophication of the marine environment become more serious and enlarge in level and scale as well, in the Changjiang Estuary and adjacent areas. This induced several serious problems in marine environment and ecosystem such as the worsening of seawater, unbanlence of marine ecosystem and high frequency of HAB.On the base of sumering the studies of the relationship of nutrient and phytoplankton inland and overseas, a series of hot point of the marine environmental ecosystem, such as the limitation status of phytoplankton, the influence of nutrient to the biomass and the structure of species, and the transformation of nutrient by phytoplankton, and so on, were studied emphatically in this thesis. The research work would give some scientific foundation to more studies on the mechanism of HAB in Changjiang Estuary and adjancent areas. The main reseach work and conclusions list as follows: 1. Field experiment and field surveys were conducted in Changjiang Estuary and adjacentareas to investagate the limitation status of nutrients to phytoplankton. The result showedthat:1.1 If there is some kind of limiting factors, the growth of phytoplankton will be limited obviously. In case of erasing the limiting factor, the phytoplankton will grow fast.1.2 At the alongshore of Changjiang Estuary, where the seawater transparency was lower than 1m, was the light limited area both in summer and in winter. The high biomass areas were located in the Zhoushan fishing ground and the north of Changjiang Estuary. The salinity of this area is about 28?1. By contrast the high biomass area in winter was moved to the south east of the investigated area, and the primary production was much lower than that in summer.1.3 By the phytoplankton limitation, the investigated area can be plotted out to 4 regions in summer. I, the light limited area. II, Phosphate latent limited area. Ill,nitrate and phosphate latent limited area. IV, nitrate latent limited area.1.4 It can be plotted out to 3 regions in winter. I, the light limited of phytoplankton area. II, P was the latent nutrient limitation area. Ill, non-nutrient latent limitation area. Light is the latent limitation at the area near the estuary; P is the latent limitation at the diluted area, and changes of season are not obvious.1.5 At the both side of the boundary of salinity 31, N and P limitation of phytoplankton changes actively. N and P are latent limited factors in summer; and there is no latent nutrient limitation in winter.1.6 There is no Si and Fe limitation of phytoplankton in the researched area2. A study was conducted to investigate the influence of nutrient to the biomass and the structure of species and the transformation of nutrient by phytoplankton in Changjiang Estuary and adjacent areas. The result showed that:2.1 In the field experiment, the biomass of phytoplankton increase with the increase of concentration of phosphate at the P limited conditios. The biomass of phytoplankton increase with the increase of concentration of nitrate at the N limited conditions.2.2 In the estuary area, under the high nutrient concentration condition the influence of concentration of nutrient is stronger than the influence of nutrient ratios. The promotion to the growth of phytoplankton of adding nutrient at the far area of the estuary is more obvious than that at the near of the estuary.2.3 From the culture results, on the conditions of blooming, the blooming species would keep the dominated species if there were abundant nutrient. It hard for the other species to get the dominated status.2.4 On the conditions that there were no blooms the changes of species of phytoplankton were obvious. Prorocentrum Donghaisense could live strongly on the condition of low nutrient concentration, and it would be replaced by diatom (Skeletonema) on the nutrient enriched condition.2.5 On the condition of high N/P ratio (higher than Redfield ratio), the uptake to n更多还原